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Ever seen a full moon in the daytime?

  1. Oct 14, 2004 #1
    I could swear i have, although when i started thinking about it could happen i got confused. You can probably tell i'm a newbie as there must be some really simple explination to this problem. It might be a bit hard to explain without a diagram, but imagine a metaphorical one with the Sun on the left of the page and Earth in the middle. Imagine you're on the hemisphere of the Earth in daylight, you are therefore on the hemisphere of the Earth closest to the Sun, thus on the left of the Earth in our metaphorical diagram. As i understand it a full moon can only occur when the moon is on the opposite side of the Earth to the Sun. So the moon is now on the right of the page. Now how can you see the bright side of the Moon when you are on the bright side of the Earth? Theres an Earth between you and the Moon.

    Now i was thinking it must have something to do with a combination of the moon being "higher" and the Earth being tilted so you are effectively leaning backwards. So i got out my globe and ball and made a little model but i still can't work it out. I did a few internet searches and couldn't find anything useful. Now im thinking three things either the problem's solution is so simple no one feels it needs explaining, you don't have a clue what im going on about or i never did see that full moon in the first place.

    Please help me out i think im losing it :bugeye:

    Cheers, Adam.
  2. jcsd
  3. Oct 14, 2004 #2


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    A full moon rises at sunset and sets at sinrise. A moon that is not quite full can still appear to be full, and can rise an hour earlier than sunset, or set an hour after sunrise. Maybe that's what you saw. There's a few other variations, such as when the moon is high or low on its inclined orbit. As the moon passes behind the Earth as seen from the Sun, it's not completely in line or there'd be a lunar eclipse. It looks very full and we still call it a full moon, but a view through binoculars will show a little bit of terminator. But even then, you're going to see it close to the horizon shortly before sunset or after sunrise. People who live in high latitudes can have the almost full moon in the daytime sky for hours.
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